The principle of hot-dip galvanized steel pipe and the application of galvanized steel pipe. Hot-dip galvanized steel pipes are galvanized for general steel pipes in order to improve the corrosion resistance of steel pipes. The galvanized steel pipe is divided into two types: hot-dip galvanizing and electro-galvanizing, hot dipped galvanized steel coil. The hot-dip galvanizing layer is thick, the cost of electro-galvanizing is low, and the surface is not very smooth. Hot-dip galvanized steel pipes and hot-dip galvanized pipes are currently the most used.
Hot-dip galvanizing, also known as hot-dip galvanizing and hot-dip galvanizing: is an effective metal anti-corrosion method, mainly used in metal structures in various industries. The rust-removed steel is immersed in a zinc solution melted at about 500 ° C to adhere the zinc layer to the surface of the steel member, thereby preventing corrosion. Hot-dip galvanizing process: finished pickling-washing-assisting plating-drying-hanging-cooling-pharmaceutical-cleaning-grinding-hot galvanizing is completed. So what is the principle of hot-dip galvanized steel pipe?
Principle: The hot-dip galvanizing layer is formed by zinc in a high-temperature liquid state in three steps:
1. The iron-based surface is dissolved by the zinc liquid to form a zinc-iron alloy phase layer;
2. The zinc ions in the alloy layer further diffuse into the matrix to form a zinc-iron mutual solution layer;
3. The surface of the alloy layer is covered with a zinc layer.
The hot-dip galvanized steel pipe has a thick, dense layer of pure zinc covering the steel surface, which prevents the steel substrate from coming into contact with any corrosive solution and protects the steel substrate from corrosion. In the general atmosphere, the surface of the zinc layer forms a very thin and dense surface of the zinc oxide layer, which is difficult to dissolve in water, so it plays a protective role on the steel substrate. If zinc oxide forms an insoluble zinc salt with other components in the atmosphere, the corrosion resistance is more desirable.
The hot-dip galvanized tube is obtained by reacting a molten metal with an iron matrix to produce an alloy layer, thereby combining the substrate and the plating layer. Hot-dip galvanizing is to pickle the steel pipe first, in order to remove the iron oxide on the surface of the steel pipe, after pickling, it is washed by ammonium chloride or zinc chloride aqueous solution or a mixed aqueous solution of ammonium chloride and zinc chloride, and then fed. Hot dip plating tank. Hot-dip galvanizing has the advantages of uniform plating, strong adhesion and long service life. The hot-dip galvanized steel pipe base and the molten plating solution are complex physical and chemical anti-galvanized steel pipes, and a corrosion-resistant structure of zinc-iron alloy layer is formed. The alloy layer is integrated with the pure zinc layer and the steel pipe base. Therefore, its corrosion resistance is strong.
Application range of hot-dip galvanized pipe:
The application of hot-dip galvanizing has also expanded correspondingly with the development of industry and agriculture. Therefore, hot-dip galvanized products are used in industry (such as chemical equipment, petroleum processing, marine exploration, metal structures, power transmission, shipbuilding, etc.), agriculture (eg sprinkler irrigation, boudoir), construction (eg water and gas transportation, wire sets) Pipes, scaffolding, houses, etc., bridges, transportation, etc. have been widely adopted in recent years. Since the hot-dip galvanized products have the characteristics of beautiful appearance and good corrosion resistance, the application range thereof is more and more extensive.